Torque transmitter and torque sensor, manufacturing method thereof, and method of measuring torque using the same

ABSTRACT

A torque transmitter for a torque sensor for measuring a torque on a shaft includes a carrier plate that includes a plurality of sensor element carrier plate regions, on each of which at least one sensor element for recording magnetic field changes is arranged, and an enclosure region formed in a substantially annular shape to enclose the shaft around a circumference of the shaft. The plurality of sensor element carrier plate regions are perpendicularly connected to the enclosure region and arranged radially within the enclosure region by being spaced apart along a circumferential direction around the circumference of the shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. application Ser. No.16/500,599 filed on Oct. 3, 2019, now issued as U.S. Pat. No.11,422,048, which is a National Stage Entry of PCT/EP2018/058253 filedon Mar. 29, 2018, which claims priority from German Application No. 102017 107 716.2 filed on Apr. 10, 2017 and German Application No. 10 2017107 111.3 filed on Apr. 3, 2017. The aforementioned applications areincorporated herein by reference in their entireties.

BACKGROUND

The invention relates to a torque transmitter for a torque sensor formeasuring a torque on a shaft by recording magnetic field changes. Theinvention also relates to a torque sensor provided with such a torquetransmitter, to a torque measurement arrangement provided with such atorque transmitter, to a method for manufacturing such a torquetransmitter and to a measurement method for measuring a torque byrecording magnetic field changes. The torque transmitter, the torquesensor and the measurement method are in particular designed to recordmagnetic field changes caused by the Villari effect, and moreparticularly to record torques in a magnetoelastic (=opposite ofmagnetorestrictive) manner.

Such torque sensors that record torques in shafts caused by magneticfield changes, and the scientific principles thereof, are described inthe following reference works:

D1 Gerhard Hinz and Heinz Voigt “Magnetoelastic Sensors” in “Sensors”,VCH Verlagsgesellschaft mbH, 1989, pages 97-152 D2 U.S. Pat. No.3,311,818 D3 EP 0 384 042 A2 D4 DE 30 31 997 A D5 U.S. Pat. No.3,011,340 A D6 U.S. Pat. No. 4,135,391 A

A structure of torque transmitters as described in D4 (DE 30 31 997 A1)has proven in particular to be particularly effective for measuringtorques in shafts and at other measurement points.

One challenge in this technology of measuring torque caused by themagnetoelastic effect and in the arrangement of sensor heads ortransmitters is that of achieving distance compensation and/orcompensation of what is known as the “RSN”. RSN stands for “rotationalsignal non-uniformity” and denotes a signal variation that occurs when ameasurement body moves or rotates, caused by various physical effects atthe measurement point. The abovementioned literature has already madeefforts to reduce the RSN; a few percent always however typicallyremain.

The invention set itself the object of providing a torque transmitter, atorque sensor provided therewith and a measurement method by way ofwhich a significant reduction of dependence on distance and reduction ofdependence on the RSN is made possible, with simple manufacturabilityand an inexpensive implementation.

SUMMARY

To achieve this object, the invention provides a torque transmitter asclaimed in claim 1. A torque sensor provided therewith and a torquemeasurement arrangement provided therewith, a manufacturing methodtherefor and a measurement method using this are the subject matter ofthe other independent claims.

Advantageous configurations are the subject matter of the dependentclaims.

According to one aspect thereof, the invention provides a torquetransmitter for a torque sensor for measuring a torque on a shaft,having a carrier plate that has a plurality of sensor element carrierplate regions, on each of which at least one sensor element forrecording magnetic field changes, in particular caused by themagnetoelastic effect, is arranged, and at least one enclosure regionthat is designed to at least partly enclose the shaft around thecircumference of the shaft, wherein at least one flexible connectionregion is provided by way of which at least one of the sensor elementcarrier plate regions is able to be pivoted relative to another sensorelement carrier plate region or relative to the at least one enclosureregion.

It is preferable for the enclosure region to be formed at least partlyby a plurality of the sensor element carrier plate regions, wherein atleast one flexible connection region is arranged between adjacent sensorelement carrier plate regions.

It is preferable for the enclosure region to have an annular design,wherein a plurality of sensor element carrier plate regions are arrangedradially within the enclosure region spaced apart in the circumferentialdirection, protrude inwardly and are able to be bent outward in theaxial direction by way of the flexible connection region.

It is preferable for each of the sensor elements to have at least onemagnetic field generation apparatus for generating a magnetic field inthe shaft and one magnetic field recording apparatus for recording achange of the magnetic field caused by a torque acting on the shaft.

It is preferable for the magnetic field generation apparatus to have atleast one generator coil and the magnetic field recording apparatus tohave at least one measurement coil, wherein at least one, a plurality ofor all of these coils are formed as planar coils on the carrier plate.

It is preferable for the carrier plate to be formed by at least onesubstrate on which the sensor elements are formed, or by at least onecircuit board.

According to a further aspect, the invention provides a torque sensorthat comprises a sleeve having a through-aperture for passing through ashaft and a torque transmitter that is arranged in or on the sleevearound the through-aperture.

The torque transmitter is in particular designed in accordance with oneof the embodiments explained above.

According to a further aspect, the invention provides a torquemeasurement arrangement for measuring the torque on a shaft, comprisingthe shaft and a torque transmitter according to one of theconfigurations described above, which

a) at least partly,b) mostly orc) completelysurrounds the shaft.

According to a further aspect, the invention provides a method formanufacturing a torque transmitter, comprising:

a) providing a carrier plateb) populating a plurality of regions of the carrier plate with sensorelements for recording magnetic field changes caused by forces on ashaft,c) providing at least one flexible connection region between the regionsthat are populated or to be populated with sensor elements such that atleast one enclosure region of the carrier plate is at least partly ableto enclose a shaft, with the flexible connection region bending.

It is preferable for step b) to comprise: manufacturing planar coils onthe plurality of regions.

A method for manufacturing a torque sensor according to a further aspectof the invention comprises performing the manufacturing method for thetorque transmitter according to one of the configurations explainedabove and embedding the torque transmitter in a sleeve having athrough-aperture for attachment to a shaft to be measured.

According to a further aspect, the invention relates to a measurementmethod for measuring a torque on a shaft, comprising:

Arranging a torque transmitter according to one of the configurationsexplained above at least partly around the shaft and recording thetorque by way of the plurality of sensor elements on regions of theshaft that are spaced apart or distributed in the circumferentialdirection.

The invention and the advantageous configurations thereof provide apossibility for a measurement that represents a considerably improvedindependence from distance and a considerably improved independence fromthe RSN. In the invention, the magnetic field is preferably not coupledlocally into a measurement point, but rather the sensor or its torquetransmitter is arranged around the shaft. Numerous arrangements comeinto consideration for this purpose, these being the subject ofparticularly preferred configurations.

To this end, a plurality of sensor elements that are each able to recordtorques on a shaft by recording magnetic field changes in amagnetoelastic manner are preferably provided. The torque transmitter isthus particularly suitable for shafts on which a magnetoelastic effect(=opposite of magnetorestrictive=Villari effect) may occur. Eddy currenteffects or local interfering fields may also influence the RSU/RSN, butalso boost the signal level.

Sensor elements that are provided on various carrier plate regions ofthe torque sensor or its torque transmitter are preferably equipped withplanar coils that are designed to generate and/or measure magneticfields on the shaft.

The sensor element carrier plate regions are preferably designed assensor cells.

The respective sensor element preferably has at least one ferrite coreto close the magnetic circuit. Magnetic field circuits to be measured,which run at least partly through the shaft, in particular on thesurface thereof, are in particular able to be formed by a fluxconcentrator, such as for example ferrite. At least two magnetic fieldcircuits having different directions from one another are preferablymeasured.

In preferred configurations, between 3 and 10 sensor element carrierplate regions are provided, which are more preferably connected to oneanother by way of flexible connection regions.

Particularly preferably, each sensor element has at least one generatorcoil, which is more preferably arranged centrally.

Particularly preferably, each sensor element has at least twomeasurement coils that are preferably connected to the generator coil bya ferrite core.

A ferrite connection is preferably arranged between a first measurementcoil and a generator coil at an angle of between 10° and 170° to aferrite connection between a second measurement coil and the generatorcoil.

Two pairs of measurement coils are preferably provided. The measurementcoils are preferably arranged in a cross shape around a generator coil.

A planar coil design having four sensor cells, including ferrite, isparticularly preferable for closing the magnetic circuit.

In one relatively simple configuration, a first and a second measurementcoil per sensor cell are sufficient for a reduced structural size. Thesignal yield is however higher with five coils.

The generator coils of the individual sensor clusters or sensor elementsmay be connected together in one preferred configuration. In anotherparticularly preferred configuration, the generator coils of individualsensor elements are operated separately.

During manufacture, it is easily possible to create different powerclasses of the torque transmitter by virtue of the fact that the numberof windings split over the individual coils is selected and manufactureddepending on the desired power class.

Magnetic fields of the individual elements flow within one another byvirtue of an alternating connection of the coils. When connected in thesame way, they cancel each other out. The choice of the connection has arelatively large influence on the suppression of the RSN. Correspondingcoils of adjacent sensor elements are particularly preferably connectedin the same way.

For a torque transmitter according to one of the configurationsdescribed in more detail above, it is thus preferable

6.1 for generator coils (26) of the magnetic field generationapparatuses (20) of at least two adjacent sensor elements (18) to beconnected

-   -   6.1.1 alternately or    -   6.1.2 in the same way        and/or    -   6.2 for a plurality of measurement coils (28) of the magnetic        field recording apparatus (22) of a sensor element (18) to be        connected    -   6.2.1 alternately or    -   6.2.2 in the same way        and/or        6.3 for mutually corresponding measurement coils (28) of the        magnetic field recording apparatuses (22) of at least two        adjacent sensor elements (18) to be connected    -   6.3.1 alternately or    -   6.3.2 in the same way.

The concept of the specific coil connection should be consideredindependently of the method for manufacturing the torque transmitter andis regarded as an independent concept. Accordingly, what is alsodisclosed here is a torque transmitter that does not contain thefeatures of the independent claims but rather is as defined in clause 1:

Clause 1:

A torque transmitter (10) for a torque sensor (12) for measuring atorque on a shaft (14), having a plurality of sensor elements (18) forrecording magnetic field changes and that are designed such that theyare able to be arranged around the shaft, wherein each of the sensorelements (18) has at least one magnetic field generation apparatus (20)for generating a magnetic field in the shaft (14) and one magnetic fieldrecording apparatus (22) for recording a change of the magnetic fieldcaused by a torque applied to the shaft (14), wherein the magnetic fieldgeneration apparatus (20) has at least one generator coil (26) and themagnetic field recording apparatus (22) has a plurality of measurementcoils (28),

1 wherein generator coils (26) of the magnetic field generationapparatuses (20) of at least two adjacent sensor elements (18) areconnected

-   -   1.1 alternately or    -   1.2 in the same way        and/or        2 wherein a plurality of measurement coils (28) of the magnetic        field recording apparatus (22) of a sensor element (18) are        connected    -   2.1 alternately or    -   2.2 in the same way        and/or        3 wherein mutually corresponding measurement coils (28) of the        magnetic field recording apparatuses (22) of at least two        adjacent sensor elements (18) are connected    -   3.1 alternately or    -   3.2 in the same way.

Preferred configurations of this further concept are given by anydesired combination of clause 1 with the features of one of claims 1 to15.

In the case of an arrangement having a first measurement coil A1, asecond measurement coil B1 and a generator coil, the measured signal ispreferably formed from a difference between the signal of the firstmeasurement coil A1 and the second measurement coil B1 (A1−B1)=torque.In the case of an arrangement having a first pair of measurement coilsA1, A2 and a second pair of measurement coils B1, B2, the pairspreferably lying opposite one another, a measured signal is preferablygenerated by (A1+A2)−(B1+B2)=torque. As an alternative or in addition,the individual amplitudes A1+A2 and/or B1+B2 are measured directly. Thepossibilities of forming a measured signal from individual sum signals(amplitudes) and/or from a difference between them help to generate asignificantly better and higher signal.

In one preferred configuration, planar coils are clipped onto a plasticsleeve as a holder and in order to keep the planar coils in a correctshape for a casting or injection molding process. In one particularlypreferred configuration, this plastic part is then either inserted intoan injection molding tool or, in another preferred configuration, isembedded and cast in a second injection mold for casting.

This preferably gives an arrangement of a complete assembly havingsensor elements that are connected to one another both mechanically andelectrically by way of a flexible connection and that are arrangedaround the measurement shaft.

In one design of an enclosed shaft for very small shaft diameters, around carrier plate may for example be provided such that the enclosureregion is formed for example as a round circuit board (PCB). Preferablytriangular sensor element carrier plate regions containing the sensorelements may be arranged toward the middle, these bending toward theaxial direction when a shaft is inserted and thus bearing on the shaft.

In the case of particularly small shafts, it is possible to apply ameasurement principle with a generator coil and measurement coils onlywith relative difficulty, since a ferrite core or as the case may beflux concentrator has manufacturing-based limits in terms of dimensions.An individual yoke made from ferrite or other magnetic booster materialmay be provided here for example in connection with a magnet.

The planar coils may accordingly for example be formed on latching pinswithin an annular enclosure region.

A circuit board or PCB, for example in the form of rigid-flex,preferably serves as carrier plate. The connection regions may reachfrom the circuit board, for example by removing material, giving athinner bending region.

Another alternative is that of using a circuit board in a semi-flexdesign.

What is accordingly particularly preferable is a configuration of themethod according to the invention for manufacturing a torquetransmitter, having one of the following steps:

12.1 singulating the regions of the carrier plate (34) that arepopulated or to be populated with sensor elements (18), wherein step c)comprises connecting the singulated regions by way of the flexibleconnection regions (40), or12.2 providing the carrier plate (34) such that the regions that arepopulated or to be populated with sensor elements (18) are connectedflexibly to one another, or12.3 providing a flexible carrier plate (34), or12.3 providing the flexible connection regions through materialmachining on the carrier plate.

Using planar coils instead of wound coils entails significant advantageswith regard to inexpensive and compact production. For example, theplanar calls may be manufactured two-dimensionally and then processedthree-dimensionally using corresponding production techniques. For moredetails in this regard, express reference is made to German patentapplication DE 10 2016 122 172.4, not yet in published form, whichexplains details with regard to the manufacture of the planar coils, theferrite cores and the casting procedures.

In one preferred configuration, the torque is measured by measuring achange of the field direction through flux gate measurement. Thistechnology is particularly suitable for very small shafts. In anotherpreferred configuration, the torque is measured by measuring changes ofthe preferred magnetic direction of the fields and eddy currents causedby surface voltages. For this purpose, a structure as known in principlefrom document D4 is used, but preferably using circuit board technologyand planar coils.

Both technologies may be used in principle to perform a homogeneousmeasurement around the shaft.

In the technology of measuring the change of the preferred magneticdirection of the fields and eddy currents caused by surface voltages, a5-coil arrangement—preferably in a cross arrangement having a centralgenerator coil—or a 3-coil technology having a generator coil and twosensor coils, preferably comes respectively at an angle of 45° (+/−10°)from the central axis. It is advantageous for no tilting or rotation tohave to be taken into account due to the arrangement of the varioussensor elements around the shaft.

By virtue of complete winding around the shaft, there are possibilitiesof eliminating for example residual magnetic fields by way of adegaussing sequence or reversing possible magnetic hysteresis faults.

A plurality of sensor elements—also called sensor clusters or sensorcells—may be used, these preferably each having at least one generatorcoil, at least one or preferably two sensor coils and ferrite for fluxboosting purposes, and being arranged around the shaft. The arrangementaround the shaft is preferably such that the measured field thusgenerated encompasses the entire measurement shaft. If there are regionsthat are not recorded in a measurement cycle, the signal noise isincreased due to the RSN. To this extent, at least four sensor elementsare preferred, and there may also be multiple sensor elements.

The complete circuit board may be produced with a semi-flex orrigid-flex design. A flex design—completely flexible circuit board—isalso theoretically possible. Such a design is however relativelyexpensive and costly in terms of manufacture, and therefore possiblyonly beneficial for specific applications.

The complete assembly including sensor elements and evaluationelectronics may be populated and tested on a blank.

Coils and electronics may preferably be manufactured using 2Dtechnologies and used as a 3D arrangement.

In the measurement method, it is preferable for sensor elements (18)that have at least two pairs of measurement coils (A1, A2; B1, B2) to beused, wherein each pair of measurement coils each measures a magneticfield circuit and the magnetic field circuit of the first pair (A1, A2)is arranged at an angle of 5° to 175°, preferably 20° to 160°, to themagnetic field circuit of the second pair (B1, B2), wherein a measuredsignal is formed from one or more of the signals of the group of signalsthat the sum (A) of the signals from the first pair of measurement coils(A1+A2), the sum (B) of the signals from the second pair of measurementcoils (B1+B2) and the difference (A−B=(A1+B1)−(B1+B2)) between the sumof the measured signals of the first pair of measurement coils (A1+A2)and the sum of the measured signals of the second pair of measurementcoils (B1+B2).

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are explained in more detailbelow with reference to the attached drawings. In the figures:

FIG. 1 shows a first exemplary embodiment of a torque transmitter forforming a torque sensor, by way of which torque on a shaft is able to berecorded by recording magnetic field changes caused by themagnetoelastic effect;

FIG. 2 shows an intermediate step for manufacturing a torque sensor fromthe torque transmitter from FIG. 1 ;

FIG. 3 shows a torque measurement arrangement having a torque sensorthat is formed with the torque transmitter from FIG. 1 , and a shaft tobe measured;

FIG. 4 shows a further exemplary embodiment of a torque transmitter;

FIG. 5 shows yet another embodiment of a torque transmitter;

FIG. 6 shows a torque measurement arrangement for measuring a torque ona shaft, comprising the shaft and a torque transmitter according to theembodiment from FIG. 4 arranged around the shaft; and

FIG. 7 shows a plan view of a comparable torque measurement arrangementthat applies another embodiment of a torque transmitter.

DETAILED DESCRIPTION

The figures illustrate various embodiments of torque transmitters 10that are able to be used in a torque sensor 12. The torque transmitters10 are used to measure a torque on a shaft 14. For this purpose, thetorque transmitter 10 is designed such that it is able to be arrangedaround the shaft 14. The arrangement is such that the torque transmitter10 at least partly, preferably mostly, and more preferably completely,encloses the shaft 14.

For this purpose, the torque transmitter 10 has an enclosure region 16.The torque transmitter 10 furthermore has a plurality of sensor elementsthat each have a magnetic field generation apparatus 20 and a magneticfield recording apparatus 22.

The magnetic field generation apparatus 20 serves to generate a magneticfield in and in particular on the surface of the shaft 14. The magneticfield recording apparatus 22 is designed to record changes of themagnetic field caused by a torque acting on the shaft 14 caused by themagnetoelastic effect. For more details on possible designs andgeometries and on the physical principles, reference is made todocuments D1 to D4 mentioned at the outset.

At least one of the apparatuses 20, 22 has at least one coil that isformed as a planar coil 24.

In particularly preferred configurations, the magnetic field generationapparatus 20 has at least one generator coil 26.

In particularly preferred configurations, the magnetic field recordingapparatus 22 has at least one measurement coil 28. An arrangement ofmeasurement coils 28 that has a first measurement coil A1 and a secondmeasurement coil B1 is preferably provided.

In particularly preferred configurations, a pair of first measurementcoils A1, A2 and a pair of second measurement coils B1, B2 is provided.Both the generator coil 26 and each of the measurement coils 28 arepreferably formed as planar coils.

Each of the coils 26, 28 furthermore encloses a magnetic fluxconcentrator 32 preferably having a ferrite core 30.

All of the sensor elements 18 are preferably manufactured ona—preferably multipart—carrier plate 34. The carrier plate may have asubstrate to which the planar coils 24 and the ferrite core 30 have beenapplied using semiconductor technology methods.

Particularly preferably, the carrier plate 34 has at least one circuitboard 36 (PCB), wherein the planar coils 24 are formed on one or moreconductor layers of the circuit board 36 and wherein the ferrite core 30of the individual magnetic flux concentrators 32 is provided inaddition, as has been disclosed and explained in detail in DE 10 2016122 172.4.

The carrier plate 34 may be constructed from a plurality of individualelements. Manufacturing on a carrier plate may also take place, whereinthe carrier plate 34 is then divided into a plurality of individualregions through material machining.

A plurality of sensor element carrier plate regions 38 are in particularformed, wherein a sensor element 18 having the corresponding coils 24,26, 28 and the corresponding magnetic flux concentrator 32 is arrangedon each of these sensor element carrier plate regions 38.

A flexible connection region 40 is furthermore provided, by way of whichindividual regions of the carrier plate 34 are connected to one anotherin a manner able to be pivoted or bent relative to one another in termsof position, wherein a wired electrical connection is provided at thesame time in order to connect the coils 24, 26, 28 to driver andevaluation electronics 42. The components of the driver and evaluationelectronics 42 may also be formed on a corresponding region of thecarrier plate 34 (electronics carrier plate region 44).

FIGS. 1 to 3 illustrate a first embodiment of the torque transmitter 10,in which a plurality of sensor element carrier plate regions 38 areconnected to one another with a flexible connection region 40 betweenthem. In the illustrated embodiment, four sensor element carrier plateregions and therefore four sensor elements 18 are provided. In otherconfigurations, three or five or even more sensor element carrier plateregions 38 having a corresponding number of sensor elements 18 areprovided.

The sensor element carrier plate regions 38 may be pivoted toward oneanother by way of the flexible connection region 40 and thus be placedaround the shaft 14.

In one preferred configuration for manufacturing such a torquetransmitter 10 according to the first embodiment, the sensor elements 18are manufactured on the carrier plate 34 and then the flexibleconnection regions 40 are manufactured by way of material removal suchthat conductor tracks for the connection between coils 26, 28 and thedriver and evaluation electronics 42 remain but the flexible connectionregion 40 is able to be bent relative to the sensor element carrierplate regions 38.

One embodiment for manufacturing a torque sensor 12 using the torquetransmitter 10 of the first embodiment is explained in more detail belowwith reference to the illustration in FIGS. 2 and 3 . FIG. 2 illustratesa carrier sleeve 46 that may be made for example from plastic and hasattachment elements for—for example temporarily—holding the sensorelement carrier plate regions 38.

In this configuration of the torque transmitter, the enclosure region 16is formed by the individual sensor element carrier plate regions 38 withthe flexible connection regions 40 between them. This is guided aroundthe carrier sleeve 46, wherein the sensor element carrier plate regions38 are fixed to the carrier sleeve 46 by way of the attachmentelements—for example retaining clips 48.

This structure of FIG. 2 may then be inserted into an injection moldingmachine and be injection-molded with plastic around the outside in orderthereby to produce a sleeve 50 in which the torque transmitter 10 isarranged around a through-aperture 52 of the sleeve. The individualelements of the torque transmitter 10 are thus embedded and packed inplastic. It is possible to pass the shaft 14 to be measured through theinterior of the through-aperture 52, giving the torque measurementarrangement 54 shown in FIG. 3 .

In one configuration, the carrier sleeve 46 remains present as furtherprotection; in another configuration, the carrier sleeve 46 is removedfollowing the injection-molding with the sleeve 50.

FIG. 3 shows the torque measurement arrangement 54 having the shaft 14and the torque sensor 12 formed by the sleeve 50 and the torquetransmitter 10.

In this case, the sensor elements 18 preferably each lie diametricallyopposite one another in pairs.

By arranging individual sensor elements around the shaft 14 to bemeasured, it is possible to compensate dependencies of the torquemeasured signal on distance changes and variations in the sensor signalcaused by other effects during rotation of the shaft (RSN), giving ameasured signal that is as independent as possible from tolerances inthe mounting of the shaft and its circumference and as independent aspossible from material inconsistencies around the circumference of theshaft.

The connection of the individual coils of the sensor elements 18 may inthis case be selected in various ways. In one configuration,manufacturing takes place such that the generator coils 26 areselectively connected in the same way as or alternately to one another,in series or in parallel, to an AC current source (not illustrated, forexample implemented in the electronics on the electronics carrier plateregion 44). In an alternative connection, the generator coils 26 areable to be driven individually or differently connected in groups.

The connection of the measurement coils 28 of the sensor elements 18 mayalso be different. A connection is preferably made such that both thesum of the signals of the first pairs A1+A2, sensitive in a firstdirection, of the measurement coils and the sum of the signals of thesecond pair (B1+B2), sensitive in a second direction, are able to bemeasured directly and the difference between these sums is able to bemeasured.

FIG. 4 illustrates a further exemplary embodiment of the torquetransmitter 10 that is suitable for smaller shaft diameters.

The enclosure region 16 here is not formed by sensor element carrierplate regions 38 that are connected to one another, but rather by adedicated annular region 56 of the carrier plate 34, wherein sensorelement carrier plate regions 38 are braced inwardly at an inner region.A flexible connection region 40 is provided in each case between thesensor element carrier plate regions 38 and the annular region 56, suchthat the sensor element carrier plate regions 38 are able to be foldedout axially from the plane of the drawing in FIG. 4 . Intended breakingpoints may for example be provided for this purpose between theindividual sensor element carrier plate regions 38.

As illustrated in FIG. 6 , the shaft 14 is able to be passed through theinterior of the annular region 56, such that the sensor element carrierplate regions 38 on the flexible connection regions 40 pivot away in anaxial direction and bear on the shaft 14 distributed around thecircumference of the shaft 14.

In the illustration from FIG. 4 , a generator coil 26 and a firstmeasurement coil A1 and a second measurement coil B1 are provided, suchthat three planar coils 24 are provided per sensor element 18, whereinthe ferrite cores 30, which are provided between the generator coil 26and each of the measurement coils A1, B1, enclose an angle between themof between 90° and 0°, and in particular between 55° and 35°.

FIG. 5 illustrates yet another embodiment for very small shaftdiameters. This configuration corresponds in terms of basic structure tothe configuration from FIG. 4 , with an annular region 56 and inwardlyprotruding sensor element carrier plate regions 38. In this case, onlytwo sensor elements 18 are provided, wherein the magnetic fieldgeneration apparatus 20 has a permanent magnet and direction changes ofmagnetic field lines are recorded by way of the magnetic field recordingapparatus 22.

FIG. 7 shows the arrangement of the annular region 56 of a furtherconfiguration of the torque transmitter 10 that corresponds in terms ofbasic structure to the structure of FIGS. 4 and 5 , wherein an evengreater number of sensor elements 18 is further provided around theshaft 14.

List of Reference Signs

10 Torque transmitter

12 Torque sensor

14 Shaft

16 Enclosure region

18 Sensor element

20 Magnetic field generation apparatus

22 Magnetic field recording apparatus

24 Planar coil

26 Generator coil

28 Measurement coil

A1 First measurement coil

B1 Second measurement coil

A2 First measurement coil

B2 Second measurement coil

30 Ferrite core

32 Magnetic flux concentrator

34 Carrier plate

36 Circuit board

38 Sensor element carrier plate region

40 Flexible connection region

42 Driver and evaluation electronics

44 Electronics carrier plate region

46 Carrier sleeve

48 Retaining clips

50 Sleeve

52 Through-aperture

54 Torque measurement arrangement

56 Annular region

What is claimed is:
 1. A torque transmitter for a torque sensor formeasuring a torque on a shaft, comprising: a carrier plate that includesa plurality of sensor element carrier plate regions, on each of which atleast one sensor element for recording magnetic field changes isarranged; and an enclosure region formed in a substantially annularshape to enclose the shaft around a circumference of the shaft, whereinthe plurality of sensor element carrier plate regions areperpendicularly connected to the enclosure region and arranged radiallywithin the enclosure region by being spaced apart along acircumferential direction around the circumference of the shaft.
 2. Thetorque transmitter of claim 1, wherein each of the at least one sensorelement comprises: at least one magnetic field generation apparatus forgenerating a magnetic field in the shaft; and at least one magneticfield recording apparatus for recording a change of the magnetic fieldcaused by the torque acting on the shaft.
 3. The torque transmitter ofclaim 2, wherein the magnetic field generation apparatus includes atleast one generator coil, and the magnetic field recording apparatusincludes at least one measurement coil, and wherein at least one of thecoils is formed as a planar coil on the carrier plate.
 4. The torquetransmitter of claim 3, wherein the generator coils of the magneticfield generation apparatuses of at least two adjacent sensor elementsare connected alternately or in parallel.
 5. The torque transmitter ofclaim 3, wherein a plurality of measurement coils are provided in themagnetic field recording apparatus of a sensor element and are connectedalternately or in parallel.
 6. The torque transmitter of claim 3,wherein mutually corresponding measurement coils of the magnetic fieldrecording apparatuses of at least two adjacent sensor elements areconnected alternately or in parallel.
 7. The torque transmitter of claim1, wherein the carrier plate is formed by at least one substrate onwhich the sensor elements are formed.
 8. The torque transmitter of claim7 wherein each of the plurality if sensor element carrier plate regionsis formed as a circuit board.
 9. The torque transmitter of claim 1,wherein the enclosure region is formed as a circuit board.
 10. A torquemeasurement system for measuring a torque on a shaft, comprising: thetorque transmitter of claim 1 arranged around the shaft, wherein thetorque is recorded by way of the plurality of sensor elements on regionsof the shaft that are distributed in the circumferential direction. 11.The torque measurement system of claim 10, wherein the sensor elementsinclude at least two pairs of measurement coils (A1, A2; B1, B2), andwherein each pair of measurement coils measures a magnetic fieldcircuit, and the magnetic field circuit of the first pair (A1, A2) isarranged at an angle of 5° to 175° to the magnetic field circuit of thesecond pair (B1, B2).
 12. The torque measurement system of claim 11,wherein a measured signal is formed based on a sum (A) of signals fromthe first pair of measurement coils (A1+A2).
 13. The torque measurementsystem of claim 11, wherein a measured signal is formed based on a sum(B) of signals from the second pair of measurement coils (B1+B2). 14.The torque measurement system of claim 11, wherein a measured signal isformed based on a difference (A−B=(A1+B1)−(B1+B2)) between a sum ofsignals from the first pair of measurement coils (A1+A2) and a sum ofsignals from the second pair of measurement coils (B1+B2).